There are more than 16,000 rental units at the Gulf, 85 percent of them condos, according to Mike Foster of the Alabama Gulf Coast Convention & Visitors Bureau.

"We're expecting a good crowd, and we expect most people will stay three nights," he said. "It's an opportunity to bring people to Alabama's Gulf Coast beaches that have never been here before."

Travel agencies that make up package deals for music festivals around the country have contacted the major rental agencies, and could buy up a couple of thousand room nights, according to Shaul Zislin, event organizer and owner of The Hangout at the foot of Ala. 59. Zislin has said he'll invest $3 million to put on the festival, which he hopes will be an annual event.

More than 60 bands are expected to perform, all groups that tour nationally, Zislin said. Thus far, headlines include the Zac Brown Band, John Legend and Alison Kraus and Union Station.

"There will be a lot of goodwill ambassadors for Alabama" once the entertainers experience the Alabama coast, Zislin said. "We're already seeing that with the production managers who come here and say, 'Wow! I never knew this was in Alabama.' This will have a tremendous impact for the area."

The surfside festival will be held between spring break and the start of summer, a perfect time for visitors since the spring rental rates are still in effect, according to Sarah Kuzma of Meyer Real Estate in Gulf Shores.

Meyer is offering a special -- stay three nights and get a fourth free -- at all of its rental units except in Gulf Shores, she said. Many of the Gulf Shores units have a different advantage, she said. They're within walking distance of the festival.

Meyer handles 1,700 rental units at the Gulf, and has already booked some of the entertainers into larger beach houses, she said.

The three-night stay with the fourth night free special is also being offered at all of the units leased by Kaiser Realty in Gulf Shores, according to Lee Kramer, marketing coordinator for Kaiser. "We're trying to bring people to the area. We don't want to raise the rates." Kaiser has 675 rental properties, including 136 houses that range from two to 12 bedrooms.

Brett Robinson Real Estate & Development in Orange Beach plans to e-mail 100,000 past guests to tell them about the May festival, according to Marie Curren, a company spokeswoman. Brett Robinson has 2,061 units to lease at the Gulf.

Brett Robinson plans to charge a 20 percent event rate increase on units that are next to the festival site, Curren said. "These are units where you can stand on the balcony and hear the bands," she said. Those Gulf-front properties include Phoenix All Suites and Island Winds East and West buildings.